Public address systems require loudspeakers which direct sound toward a particular location, and loudspeakers used for such services are generally directional loudspeakers designed for conveying intelligence. Horn projectors have proven to be particularly suitable for such service, and may be used in buildings or outside of buildings, either permanently installed or as portable units. In all applications, the loudspeaker must be directed toward a particular location, and adjustable mounts are generally provided to facilitate this adjustment.
Further, some loudspeakers, particularly certain horn loudspeakers, project sound with a greater angle of dispersion in one plane than in the plane normal thereto, the planes being referred to as the major and minor axes of propagation of the speaker. It is necessary to align the axes of such speakers with the major and minor axes of the area to be serviced.
One type of adjustable mount which is in commercial use has a mounting plate with an outwardly extending circular flange which is removably attached by a bolt and wing-nut to a circular flange extending outwardly from a horn loudspeaker. The horn loudspeaker may be rotated on the bolt to the desired angle and thereafter locked in place by tightening the wing-nut. In some cases, the mounting plate is mounted on a base for rotation about an axis normal to the bolt to provide additional adjustability.
U.S. Pat. No. 2,922,609 of W. D. Collier dated Jan. 26, 1960, entitled ADJUSTABLE MOUNT discloses another mounting structure in which a based supports a threaded pin and a circular disc is rotatably journaled on the pin. The disc has a recess in the form of part-cylindrical slot, and a cradle with a mating part-cylindrical surface is slidably disposed within the recess. The cradle has an elongated slot which accommodates the pin and permits the cradle to translate in the recess of the plate. The item to be positioned is mounted on the cradle, and by translating the cradle and rotating the disc, the item may be directed as desired. A nut engages the threaded pin, and tightening the nut locks the structure.
In another mounting structure, a load carrying element in the form of a part-cylindrical ball is mounted on a retaining yoke, as disclosed in U.S. Pat. No. 4,515,336 of William H. Fischer dated May 7, 1985, and entitled BALL AND SOCKET MOUNT FOR OPTICAL SENSING SOURCE AND/OR DETECTOR DEVICES. Devices of this type provide limited adjustability due to interference of the yoke.
U.S. Pat. No. 4,415,136 of Paul R. Knoll dated Nov. 15, 1983, and entitled PEDESTAL FOR CONSOLES describes still another mounting structure capable of movement against constant frictional restraint in which a part spherical member is journaled against a seat carried by a base.
For purposes of adjusting the direction of sound radiation of a loudspeaker that has a wider sound dispersion in one plane than in the plane normal thereto, it is generally desirable to adjust the general direction of propagation of sound first and thereafter align the sound pattern to the area being serviced. Accordingly, it is an object of the invention to provide a mounting structure with independent adjustment means operable to adjust the direction of propagation and the alignment of the pattern of the sound propagation with the area to be serviced, and to provide means for separately and independently locking each adjustment means against movement.
In practice, loudspeaker mounting structures of the type described above have proven to have disadvantages. The mounting structure is independent of the connecting cable to the loudspeaker. Further, the cable generally extends from a portion of the loudspeaker housing remote from the adjustable mounting means, and the cable is exposed and subject to wear and abuse.
It is an object of the invention to provide a mounting structure particularly designed for use with directional loudspeakers, such as horn projectors. In particular, it is an object of the invention to provide such a structure with a base designed to facilitate mounting on walls or other structures.
It is also an object of the invention to provide a mounting structure which has means for guiding and protecting the connecting cable for the loudspeaker. Further, it is an object of the invention to provide a mounting structure for a loudspeaker which may be directly mounted on a junction box and the cable of the loudspeaker connected within the junction box to wires for energizing the loudspeaker.